Reflector and lamp comprised thereof

ABSTRACT

Embodiments of a reflector and a lamp that utilizes the reflector and light-emitting diode (LED) devices to generate an optical intensity distribution substantially similar to that of a conventional incandescent light bulb. The lamp can include a heat dissipating assembly with one or more heat dissipating elements disposed annularly about the envelope and spaced apart from the envelope in order to promote convective airflow. In one embodiment, the reflector operates as a total internal reflection (TIR) lens.

BACKGROUND

1. Technical Field

The subject matter of the present disclosure relates to lighting andlighting devices and, more particularly, to embodiments of a lamp thatutilizes a directional light source and a reflector to generate anoptical intensity distribution substantially similar to the opticalintensity distribution of common incandescent lamps.

2. Description of Related Art

Incandescent lamps (e.g., integral incandescent light bulbs and halogenlight bulbs) mate with a lamp socket via a threaded base connector (i.e.an “Edison base” in the context of an incandescent light bulb), abayonet-type base connector (i.e. bayonet base in the context of anincandescent light bulb), or other standard base connector. Theseincandescent lamps are often in the form of a unitary package thatincludes components to operate the lamps from a source of standardelectrical power (e.g., 110 V and/02 220 V AC and/or 12 VDC and/or DCbatteries). In the case of an incandescent lamp, the lamp comprises anincandescent filament operating at high temperature and radiatingefficiently excess heat into the ambient. Moreover, the majority ofincandescent lamps are naturally omni-directional light sourcesproviding light with a substantially uniform optical intensitydistribution (a “intensity distribution”).

Energy efficient lighting technologies include solid-state lightingdevices such as LEDs, lamps having LEDs as a light source (LED lamp),and other LED-based devices often have performance that is superior toincandescent lamps. The superior performance of a solid-state lightingdevice can be quantified by its useful lifetime (e.g., its lumenmaintenance and its reliability over time) and its higher efficacy asmeasured in Lumens per Electrical Watt (LPW)). For example, the lifetimeof an incandescent lamp is typically in the range of approximately 1,000to 5,000 hours as compared to the lifetime of LED-based lamps typicallyexceeding 25,000 hours. In another example, the efficacy of anincandescent lamp is typically in the range of 10 to 30 LPW as opposedto the efficacy of LED-based lamps being typically in the range of 40 to100 LPW.

LED-based devices do have one significant disadvantage in someapplications; namely, LED-based devices are highly unidirectional bynature. For example, common LED-based devices are flat and usually emitlight from only one side of the device. Thus, although superior withrespect to certain performance aspects, the intensity distribution ofmany commercially available LED lamps designed to be suitablealternative and/or replacement for incandescent lamps cannot replicatethe intensity distribution of incandescent lamps in satisfactory manneror to a sufficient extent.

Another challenge related to solid-state lighting technologies is theneed to find a way to dissipate heat adequately. For example, LED-baseddevices are highly sensitive to temperature variations with respect tothe performance and reliability of the LED-based devices as compared toincandescent lamps containing incandescent or halogen filaments. Thistemperature sensitivity challenge is often addressed by placing a heatsink in contact with or in thermal contact with the LED-based device.Unfortunately, the heat sink, depending on the placement thereof, mayblock all or a portion of the light that the LED lamp emits, thus, maylimit further the ability of the LED lamp to generate light with a moreuniform optical intensity distribution. Moreover, physical constraintson lamps such as regulatory limits that define maximum dimensions forall lamp components, including light sources, limit further an abilityto dissipate heat sufficiently and efficiently for LED-based lamps

Accordingly, a LED lamp that further encourages households andcommercial establishments to convert from conventional incandescentlamps and to install more energy efficient lamps (e.g., LED lamps) isdesirable. Consequently, a need exists for a lamp that more closelygenerates light with a uniform optical intensity distribution that isconsistent with an incandescent lamp while delivering superiorperformance with respect to average lifespan of the lamp and toefficacy. Additionally, a need exists for a solid-state lighting devicesuch as an LED lamp that dissipates heat effectively and efficientlywithout adversely affecting the uniformity of the optical intensitydistribution of the LED lamp.

BRIEF SUMMARY OF THE INVENTION

The present disclosure describes, in one embodiment, a lamp thatcomprises an envelope forming an interior volume and a reflectordisposed in the interior volume. The reflector comprises a facet havinga first end and a second end proximate, respectively, an outerperipheral edge and a center axis of the reflector. The facet has anexterior facet profile with a first face, a second face opposing thefirst face, and a facet edge disposed therebetween. In one example, thefirst face and the second face are configured to at least partiallyreflect light.

The present disclosure describes, in one embodiment, a lamp thatcomprises a light-emitting diode device with an optical axis and areflector spaced apart from the light-emitting diode device. Thereflector has a center axis aligned with the optical axis and comprisesa plurality of facets disposed circumferentially about the center axis.The facets have an exterior facet profile with a first face, a secondface opposing the first face, and a facet edge disposed therebetween.The lamp also comprises an envelope in surrounding relation to thereflector. The lamp further comprises a heat dissipating assembly with aheat dissipating element spaced apart from the outer surface of theenvelope forming an air gap.

The present disclosure describes, in one embodiment, a reflector for usein a lamp. The reflector comprises a plurality of facets disposedcircumferentially about a center axis that form an outer peripheraledge. The facets have an exterior facet profile with a first face, asecond face opposing the first face, and a facet edge disposedtherebetween. In one example, the exterior facet profile comprises afirst profile proximate the outer peripheral edge of the reflector and asecond profile proximate the center axis that is different fromdifferent from the first profile.

Other features and advantages of the disclosure will become apparent byreference to the following description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made briefly to the accompanying drawings, in which:

FIG. 1 depicts a schematic diagram of a side view of one exemplaryembodiment of a lamp with a directional light source and a reflectorthat disperses light from the light source with uniform opticalintensity;

FIG. 2 depicts a side view of another exemplary embodiment of a lampwith a directional light source, a reflector, and heat dissipatingelements to achieve uniform optical intensity;

FIG. 3 depicts a perspective view an exemplary light diffusing assemblyfor use in the lamp of FIGS. 1 and 2;

FIG. 4 depicts a side, cross-section view of the exemplary diffuser ofFIG. 3;

FIG. 5 depicts a perspective view of an exemplary reflector for use inthe light diffusing assembly of FIGS. 3 and 4 and the lamps of FIGS. 1and 2;

FIG. 6 depicts a top view of a single facet of the reflector of FIG. 5;

FIG. 7 depicts a front view of the single facet of the reflector takenat line 7-7 in FIG. 6;

FIG. 8 depicts a side, cross-section view of the single facet of thereflector taken at line 8-8 in FIG. 6 that illustrates one configurationof the exterior profile of the facet;

FIG. 9 depicts a cross-section view of reflector taken at line 9-9 inFIG. 5 that illustrates a first profile and a second profile of theexterior profile of the single facet;

FIG. 10 depicts an exemplary reflector for use in the light diffusingassembly of FIGS. 3 and 4 and the lamps of FIGS. 1 and 2 that has anupward conical shape;

FIG. 11 depicts an exemplary reflector for use in the light diffusingassembly of FIGS. 3 and 4 and the lamps of FIGS. 1 and 2 that has adownward conical shape;

FIG. 12 depicts an exemplary reflector for use in the light diffusingassembly of FIGS. 3 and 4 and the lamps of FIGS. 1 and 2 that has aconical shape with curved and/or curvilinear features;

FIG. 13 depicts a perspective view of an exploded assembly of anexemplary reflector for use in the light diffusing assembly of FIGS. 3and 4 and the lamps of FIGS. 1 and 2 that has multiple-piececonstruction; and

FIG. 14 depicts a plot of an optical intensity distribution profile foran embodiment of a lamp such as the lamps of FIGS. 1 and 2.

Where applicable like reference characters designate identical orcorresponding components and units throughout the several views, whichare not to scale unless otherwise indicated.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exemplary embodiment of a lamp 100. The lamp 100comprises a base 102, a central axis 104, an upper pole 106, and a lowerpole 108. The upper pole 106 and the lower pole 108 are located on thecenter axis 104 and define a spherical co-ordinate system that is usefulto describe the spatial distribution of illumination and the intensityof such illumination that the lamp generates. The spherical co-ordinatesystem used in this description of the invention comprises an elevationor latitude co-ordinate θ and an azimuth or longitudinal co-ordinate φ.For the purposes of the description below, the elevation or latitudeco-ordinate θ shall be defined as being equal to zero degrees (0°) atthe upper pole 106 on the central axis 104 and as being equal to onehundred eighty degrees) (180° at the lower pole 108 on the center axis104.

The lamp 100 also comprises a light diffusing assembly 110, a heatdissipating assembly 112, and a light source 114 that is capable ofgenerating light. The light diffusing assembly 110 includes an envelope116 with an outer surface 118 and an inner surface 120 that surrounds aninterior volume 122. The light diffusing assembly 110 also includes areflector 124 located within the interior volume 122 of the envelope.The reflector 124 has a top 126 and a bottom 128, wherein light from thelight source 114 enters the reflector 124 at the bottom 128.

Examples of the lamp 100 generate comfortable room lighting, e.g.,similar to incandescent A-19 lamps. As set forth more below, thereflector 124 can include a plurality of facets disposedcircumferentially about the central axis 104. These facets have geometrythat reflect and/or diffuse light from the light source 114, thusenhancing the characteristics of illumination of the lamp 100. In oneexample, the facets form and/or reflect light in a manner consistentwith a total internal reflection (TIR) lens and similar losslessreflective properties. As a reflector, light from the light source 114strikes surfaces of the facets at such a steep angle with respect to thenormal of the surface (or greater than a so-called critical angle forlens material) that the light cannot pass through the surface andinstead reflects off these surfaces as if the surfaces were covered witha material that is reflective.

The outer surface 118 and the inner surface 120 of the envelope 116 aremade from a light-transmissive material. In some examples, thelight-transmissive material used to make the envelope 116 is selectedfrom the group comprising glass, acrylic, diffusing polycarbonate, othercommercially available diffusing polymers (e.g., Teijin ML5206,MAKROLON®), or any combination thereof. In other examples, the materialthat the envelope 116 comprises is inherently light-diffusive (e.g.,opal glass) or can be made light-diffusive by means of a variety ofmethods such as frosting and/or texturizing the outer surface 118 and/orthe inner surface 120 in order to increase light diffusion. In oneexample, the envelope 116 comprises a coating (not shown) such as enamelpaint and/or other light-diffusive coating (available, for example, fromGeneral Electric Company, New York, USA). Suitable types of coatings arefound on common incandescent and fluorescent light bulbs. In yet anotherexample, manufacturing techniques may be deployed that embedlight-scattering particles, fibers, and/or other light scattering mediain the material that comprises the envelope 116.

At a relatively high level, use of the reflector 124 in embodiments ofthe lamp 100 generate light with a relative optical intensitydistribution (or “optical intensity”) at a level of approximately100±20% over the range of values for the latitudinal co-ordinate 0between zero degrees) (0° and one hundred thirty-five degrees) (135° orgreater, where 100% corresponds to the average intensity over the range.In one embodiment, the lamp 100 maintains a relative optical intensityof 100±20% for values of the latitudinal co-ordinate of less than orapproximately equal to one hundred fifty degrees (150°. These opticalintensity distribution profiles comply with target values for opticalintensity that the Department of Energy (DOE) sets for solid-statelighting devices as well as other applicable industry standards andratings (e.g., ENERGY STAR®). The levels and distributions of opticalintensity of the lamp 100 render the lamp 100 a suitable replacementfor, or alternative to, conventional incandescent light bulb. Moreover,the physical characteristics and dimensions of the lamp 100 aresubstantially consistent with the physical profile of such commonincandescent light bulbs, wherein the outer dimension defines boundarieswithin which the lamp 100 must fit. Examples of this outer boundarydimension meet one or more regulatory limits or standards (e.g., ANSI,NEMA, etc.). In one embodiment, the envelope 116 can be substantiallyhollow and have a curvilinear geometry (e.g., spherical, spheroidal,ellipsoidal, toroidial, ovoidal, and/or numerically generated freeformshape) that diffuses light.

The reflector 124 fits within the interior volume 122 of the envelope116 in a position to intercept light emitted by the light source 114. Asshown in FIG. 1, this position is spaced apart from the light source 114and the upper, or top, part of the envelope 116. The amount of spacingmay depend on construction of the reflector 124 as well other featuresand properties of the lamp 100. In one construction, the peripheral edgeof the reflector 124 is secured to the inner surface 120 of the envelope116 with an adhesive or an adhesive material. In other constructions,the inner surface 120 of the envelope 116 and the peripheral edge of thereflector 124 can comprise one or more complimentary mating elements(e.g., a boss and/or a ledge, a tongue, and/or a groove). Thecombination of these complimentary mating elements secures the reflector124 in position. In another construction, the mating elements may form asnap-fit, a plastic weld joint, or have another mating configurationthat prevents the reflector 124 from moving from the position (e.g., asshown in FIG. 1) to any significant extent.

FIG. 2 depicts a side view of another exemplary embodiment of a lamp 200with a central axis 204, a light diffusing assembly 210, a heatdissipating assembly 212, and a light source 214. The light diffusingassembly 210 has an envelope 216 with an outer surface 218 and an innersurface 220 in surrounding relation to a reflector 224. The light source214 may include a solid-state device with one or more light-emittingelements such as light-emitting diode (LED) devices. The heatdissipating assembly 212 comprises a base element 229 in thermal contactwith the light source 214 and at least one heat dissipating element 230coupled to the base element 229. The heat dissipating element 230promotes conduction, convection, and radiation of heat away from thelight source 214. In one embodiment, the heat dissipating element 230has a peripheral edge 232 that forms the outer periphery or shape of theheat dissipating elements 230. The peripheral edge 232 comprises anouter peripheral edge 234 and an inner peripheral edge 236 proximate theouter surface 218 of the envelope 216. A gap 238 separates the innerperipheral edge 236 of the periphery edge 232 of the heat dissipatingelement 230 from the outer surface 218 of the envelope 216. The gap 238spaces the end of the heat dissipating elements 230 away from the outersurface 218 of the envelope 216, which facilitates airflow andconvection currents to promote cooling and thermal dissipation of heataway from the lamp 200, while also improving the intensity distributionin the latitudinal direction.

In one exemplary embodiment, the light source 214 is a planar LED-basedlight source that emits light into a hemisphere having a Lambertianintensity distribution, compatible with the light diffusing assembly 210for producing omni-directional illumination distribution. In oneembodiment, the planar LED-based Lambertian light source includes aplurality of LED devices (e.g., LEDs 232) mounted on a circuit board(not shown), which is optionally a metal core printed circuit board(MCPCM). The LED devices may comprise different types of LEDs. In oneembodiment, at least one of a first type of LED may be combined with atleast one of a second type of LED, wherein the first and second types ofLEDs have respective spectra and intensities that mix with each other inorder to render white light of a desired color temperature and colorrendering index (CRI). In one embodiment, the first type of LED outputwhite light, which in one example has a greenish rendition (achievable,for example, by using a blue or violet emitting LED chip that is coatedwith a suitable “white” phosphor). The second type of LED output redand/or orange light (achievable, for example, using a GaAsP or AlGaInPor other epitaxy LED chip that naturally emits red and/or orange light).The light from the first type of LED and from the second type of LEDblend together to produce improved color rendition. In anotherembodiment, the planar LED-based light source can also comprise a singleLED or an array of LED emitters incorporated into a single LED device,which may be a white LED device and/or a saturated color LED deviceand/or so forth. In another embodiment, the LED emitter is an organicLED comprising, in one example, organic compounds that emit light.

FIG. 3 shows an exemplary embodiment of a light diffusing assembly 300.FIG. 4 illustrates a side cross-sectional view taken along line 4-4 ofFIG. 3. In FIG. 3, the light diffusing assembly 300 is suitable for useas part of a lamp (e.g., lamp 100 and lamp 200 of FIGS. 1 and 2,respectively). The light diffusing assembly 300 has opticalcharacteristics that can disperse light to cause the lamp to create theintensity distributions discussed above. In the perspective view of FIG.3, the light diffusing assembly 300 has an envelope 302 with a spheroidgeometry that terminates at an opening 304. The envelope 302 is hollow,thus forming an interior volume 306. A reflector 308 is disposed in theinterior volume 306. The reflector 308 can have a top 310 and a bottom312. Collectively, the configuration of the envelope 302 and thereflector 308 forms one or more active optical areas, which include atransmissive outer area formed by all and/or part of the envelope 302and a reflective area formed, at least in part, by the reflector 308. Inone embodiment, the reflector 308 permits little or no light to pass tothe transmissive outer area, e.g., to the top portion of the envelope302.

The top 310 of the reflector 308 may be coated with a reflectivematerial (e.g., silver foil) in order to further reduce the amount oflight that passes through the reflector 308. In one embodiment, thereflector 308 is configured to reflect light so the trajectory of thereflected light has a latitudinal value (e.g., latitudinal value θ ofFIG. 1) in the range of ninety degrees (90°) to one hundred eightydegrees (180°).

The opening 304 provides access to the interior volume 306 of theenvelope 302. The opening 304 has a diameter d that, in one example, issized and configured to fit about a light source (e.g., light source114, 214 of FIGS. 1 and 2) when the light diffusing assembly 300 is inposition on a lamp (e.g., lamp 100, 200 of FIGS. 1 and 2). In oneexample, the light diffusing assembly 300 is configured so that thelight source sits outside of and/or on the periphery of the majority ofthe interior volume 306.

In the cross-section of FIG. 4, the light diffusing assembly 300 isshown to have a contour and dimensions (e.g., a height dimension H andan outer diameter D) that define the curvilinear features of thespheroid geometry. The reflector 308 functions to reflect light mostlythrough the transmissive outer areas of the envelope 302 rather thanback to and/or through the opening 304. The diameters (e.g., diameter Dand diameter d) along with the optical properties of the envelope 302that defines the transmissive outer area and the reflector 308 determinethe intensity distribution of embodiments of the lamps contemplatedherein. Examples of the transmissive outer area predominantly allowlight to transmit from the interior volume 306 out through the envelope302. However, the transmissive outer area and the reflector 308 may alsoexhibit combinations of light-reflecting and/or light-transmittingproperties to provide intensity distributions consistent with the lookand feel of incandescent light bulbs as well as to meet the variousindustry standards discussed herein. In one example, the intensitydistribution of light through the transmissive outer area issignificantly greater than the intensity distribution of light passingthrough the reflector 308.

Variations in the contour of the envelope 302 can influence theintensity distribution the light diffusing assembly 300 exhibits (e.g.,by defining the features of the spheroid geometry in the transmissiveouter area). In one example, the spheroid geometry of the lightdiffusing assembly 300 has a generally flatter shape than a sphere,e.g., having a shape of an oblate spheroid, thus creating the flattened(or substantially flattened) top and peripheral radial curvatures asshown in FIG. 4.

Examples of the envelope 302 of the light diffusing assembly 300 may beformed monolithically as a single unitary construction or as componentsthat are affixed together. Materials, desired optical properties, andother factors (e.g., cost) may dictate the type of constructionnecessary to form the geometry (e.g., the spheroid geometry) of thelight diffusing assembly 300. In another exemplary embodiment, the lightdiffusing assembly 300 has a multi-component construction in which thespheroid geometry can be approximated by a discrete number of planarsheet diffusers assembled in an axisymmetric arrangement following thesurface of a spheroid. In certain embodiments, sheet diffusers areutilized because the sheet diffusers can exhibit potentially highdiffusion of light with relatively low loss or absorption of lightcompared with monolithically-formed, three-dimensional diffusers.Multi-component structures can exhibit the same optical properties asthe diffusive envelope 302 discussed above (e.g., land, thus,embodiments of the lamp (e.g., lamp 100, 200 of FIGS. 1 and 2) of thisdisclosure can exhibit the same distribution pattern with similarintensity distribution as discussed in connection with the lamp 100above. However, multi-component structures may permit complex geometriesnot necessarily amenable to certain materials and/or processes includingmonolithic formations of the diffuser as discussed herein.

FIGS. 5, 6, 7, 8, and 9 illustrate an exemplary reflector 500 suitablefor use as the reflectors 124, 224 of FIGS. 1 and 2 and reflector 308 ofFIGS. 3 and 4. FIG. 5 depicts a perspective view of the reflector 500.The reflector 500 has a body 502 with a central axis 504 and an outerperipheral edge 506. The body 502 has a first side 508 and a second side510 that correspond to, respectively, the bottom and the top in theembodiments of FIGS. 1, 2, 3, and 4. The body 502 includes a pluralityof facets (e.g., a first facet 512 and a second facet 514) disposedcircumferentially about the central axis 504. The facets 512, 514 havean exterior facet profile with a pair of opposing faces (e.g., a firstface 516 and a second face 518) that form a facet edge 520 on the secondside 510 of the reflector 500. In one embodiment, the first face 516 andthe second face 518 of the facets 512, 514 are configured to reflect afirst amount of light emitted by the light source back to a firstportion of the envelope (e.g., envelope 116, 216 of FIGS. 1 and 2) andto refract a second amount of light emitted by the light source to asecond portion of the envelope (e.g., envelope 116, 216 of FIGS. 1 and2). In one example, the first portion is subjacent (and/or closer to thelight source) to the second portion along the optical axis. As alsoshown in FIG. 5, the faces 516, 518 of adjacent facets 512, 514 can forma valley 522.

Examples of the reflector 500 can be rotationally symmetric, wherein theexterior facet profile and other features are substantially the same forall of the facets (e.g., facets 512, 514) that make up the body 502. Inone example, the number of facets (e.g., facets 512, 514) is in therange of about twenty to about forty, although dimensions and otherfactors (e.g., optical properties) can cause the number of facets 512,514 to increase and decrease, as desired. As shown in FIG. 5, the facets512, 514 are generally equally spaced about the central axis 504.However, this disclosure does contemplate other configurations of thereflector 500 in which the distance between adjacent facets 512 (e.g.,as measured between the facet edge 520 on adjacent facets 512) variesacross the construction of the body 502. In one example, the first side508 forms a surface that is substantially flat and smooth and, thus,exhibits no or very weak optical properties. Moreover, as set forth insome examples below, the construction of the body 502 can incorporateshapes and features that cause the first side 508 and the second side510 to form convex, concave, and otherwise non-uniform surfaces, e.g.,from the outer peripheral edge 506 towards the central axis 504.

The valleys 522 can have various shapes and forms that can influence theoptical properties of the reflector 500. In one example, the end offirst face 514 and the end of second face 516 meet at a point (orsubstantially sharp interface) that forms the valley 522 into a “V”shape. In other examples, the valley 522 includes a flat segment and/orradial segment that mates with the end of the first face 514 and the endof the second face 516. This configuration forms the valley 522 with aflat bottom or, in the case of the radial segment, with a “U” shape. Thedimensions of the flat segment (and radial segment) can be minimized toachieve an acceptable level of performance and internal reflection fromthe reflector 500. Likewise, in one embodiment, the exterior facetprofile can be rounded along at least a portion of the facet edge 520,wherein such rounding may result from manufacturing, finishing, and/orpolishing processes. However, the radii of such rounded peaks should beminimized in order to achieve acceptable performance and internalreflection from the reflector 500.

FIG. 6 depicts a top view of the reflector 500 with only the facet 512in view to focus the discussion hereinbelow on one exemplaryconstruction of the facets of the reflector 500. In particular, theexample of FIG. 6 illustrates that the facet edge 520 extends from theouter peripheral edge 506 towards the central axis 504. The facet edge520 terminates at an aperture 524, which is coaxial with the centralaxis 504 and extends through the body 502. This configuration of theaperture 524 represents an area of the body 502 where material ismissing. In some examples, the reflector 500 may include an element thatcovers all and/or part of the aperture 524. This element may form adome, flat, or other shape as necessary to promote appropriate opticalproperties of the reflector 500.

As best shown in FIG. 7, which is a front view of the facet 512 of FIG.6 taken at line 7-7, the exterior facet profile has an upper form factor(e.g., a triangular form factor 526) and a lower form factor (e.g., arectangular form factor 528). The triangular form factor 526 includesthe first face 514, the second face 516, and the facet edge 520. Therectangular form factor 528 includes a pair of parallel sides (e.g., afirst parallel side 530 and a second parallel side 532) and a bottomside 534, which in one example is formed by the bottom surface of thereflector 500. The exterior facet profile also includes a matingboundary, shown in phantom lines and generally designated by the numeral536. The mating boundary 536 defines a geometric plane between the endsof the first face 516 and the second face 518.

In one example, the mating boundary 536 represents the interface betweenthe triangular form factor 526 and the rectangular form factor 528. Afirst angle 538 and a second angle 540 define the angle created betweenthe mating boundary 536 and the first face 516 and the second face 518,respectively. In one example, the first angle 538 and the second angle540 are substantially equal. This disclosure also contemplates examplesof the exterior facet profile in which the first angle 538 and thesecond angle 540 have a value in the range of about 45° to about 55°,and in one particular configuration the value is about 50°. In otherexamples, the first angle 538 is different from (e.g., greater thanand/or less than) the second angle 540.

FIGS. 8 and 9 show views of the facet 512 taken at, respectively, line8-8 and line 9-9 of FIG. 6. In the example of FIG. 8, which is a side,cross-section view, the facet 512 has a first end 542, proximate theouter peripheral edge 506, and a second end 544 proximate the aperture522. The facet edge 520 has a slope which changes from the first end 542to the second end 544. The extent and/or degree to which the facet edge520 slopes depends, in one example, on the change in the exterior facetprofile from the first end 542 to the second end 544. The outer exteriorprofile of the facet 512 can remain constant, i.e., the first angle 538and the second angle 540 in FIG. 7 have the same value from the firstend 542 to the second end 544. In other examples, and as best shown inFIG. 9, the facet 512 can have a first exterior facet profile 546 (also,“first profile 546”) and a second exterior facet profile 548 (also“second profile 548”), wherein the ratio of the first profile 546 to thesecond profile 548 controls the degree of slope of the facet edge 520.The ratio can have a value in the range of about 1 to about 3, althoughthis disclosure contemplates other configurations in which the ratiofalls outside of this range. Modifications in the ratio can change theheight of the facet 512 across the facet edge 520 from the first end 542to the second end 544. In FIG. 9, for example, the first profile 546 isdimensionally larger than the second profile 548. This configurationcauses the facet edge 520 will slope or grade downwardly (e.g., in adirection from the first side 508 toward the second side 510) as thefacet edge approaches the center axis 504. In other examples, the firstprofile 546 is dimensionally smaller than the second profile 548, thuscausing the facet edge 520 to slope or grade upwardly (e.g., in adirection from the first side 508 toward the second side 510).

As set forth above, the reflector 500 can exhibit optical propertiesthat are similar to TIR lenses that do not require any secondaryprocessing such the application of a reflective coating, treatment, orlayer to any of the surfaces of the reflector 500. In one embodiment,the reflector 500 consists of a single unitary piece in order tofacilitate ease of manufacture and to help reduce costs and expensesrelated to the manufacture of the reflector 500. In another embodiment,a reflective coating or layer (e.g., silver foil or metallic paint) maybe selectively applied to the top surfaces of the reflector 500, e.g.,along the edge 520 of the facets 512 and/or the central aperture 524.This reflective coating can reduce the amount of light emitted from alight source (e.g., the light source 114, 214 (FIGS. 1 and 2)) thatpasses through the reflector 500 and continues subsequently through theupper portion of a lamp (e.g., the lamp 100, 200 (FIGS. 1 and 2) and/orof a light diffusing assembly (e.g., light diffusing assembly 110, 210,310 (FIGS. 1, 2, and 3)).

The following examples further illustrate alternate configurations anddesigns for reflectors 124, 224 of FIGS. 1 and 2, reflector 308 of FIGS.3 and 4, and reflector 500 of FIGS. 5, 6, 7, 8, and 9.

EXAMPLES

FIGS. 10, 11, 12, and 13 illustrate various form factors andconstructions for embodiments of reflectors this disclosure contemplatesherein. Examples of reflector 600 and 700 of FIGS. 10 and 11 having aconical reflector shape. In FIG. 10, the reflector 600 has an upwardconical shape that may result when the center point of the outer profile(e.g., outer profile 546 of FIG. 9) is offset, or moved downwardly,along the axis 604 relative to the inner profile (e.g., inner profile548 of FIG. 9). The reflector 700 of FIG. 7 has a downward conical shapethat may result when the center point of the outer profile (e.g., outerprofile 546 of FIG. 9) is offset, or moved upwardly, along the axis 704relative to the inner profile (e.g., inner profile 548 of FIG. 9). FIG.12 illustrates another configuration for the reflector 800 in which thesurface at the bottom 808 of the reflector 800 can form a conical shapewith curved and/or curvilinear features.

FIG. 13 depicts an exploded view of an exemplary construction of areflector 900. This construction utilizes multiple pieces (e.g., a firstpiece 902, a second piece 904, and a third piece 906) to form the facetsof the reflector 900. These multiple pieces can form one or more annularrings (e.g., the first piece 902 and the second piece 904) and an innerdisc (e.g., the third piece 906). In one example, each of the pieces902, 904, 906 include facets that conform to the features disclosedherein. In one embodiment, assembly of the pieces 902, 904, 906 togethercomplete the structure of the reflector 900 and, accordingly, form thefacets that are useful to manipulate light as required for use in thelamps.

FIG. 14 illustrates a plot 1000 of an optical intensity distributionprofile 1002 (or “optical intensity” profile 1002). Data for the plot1000 was gathered using from an embodiment of the lamp having areflector substantially similar to the reflector shown in FIGS. 5, 6, 7,8, and 9 and described above. As the optical intensity profile 1002illustrates, the lamp achieves a mean optical intensity 1004 ofapproximately 100±20% at a latitudinal co-ordinate up to at least onehundred thirty-five degrees (135°).

As used herein, an element or function recited in the singular andproceeded with the word “a” or “an” should be understood as notexcluding plural said elements or functions, unless such exclusion isexplicitly recited. Furthermore, references to “one embodiment” of theclaimed invention should not be interpreted as excluding the existenceof additional embodiments that also incorporate the recited features.

This written description uses examples to disclose embodiments of theinvention, including the best mode, and also to enable any personskilled in the art to practice the invention, including making and usingany devices or systems and performing any incorporated methods. Thepatentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those skilled in the art. Suchother examples are intended to be within the scope of the claims if theyhave structural elements that do not differ from the literal language ofthe claims, or if they include equivalent structural elements withinsubstantial differences from the literal language of the claims.

What is claimed is:
 1. A lamp, comprising: an envelope forming aninterior volume; and a reflector disposed in the interior volume, thereflector comprising a facet having a first end and a second endproximate, respectively, an outer peripheral edge and a center axis ofthe reflector, the facet having an exterior facet profile with a firstface, a second face opposing the first face, and a facet edge disposedtherebetween, wherein the first face and the second face are configuredto at least partially reflect light.
 2. The lamp of claim 1, wherein theexterior facet profile comprises a first form factor in which the firstface and the second face form the sides of a triangle.
 3. The lamp ofclaim 1, wherein the first face forms a first angle and the second faceforms a second angle with a geometric plane that extends between an endof the first face and an end of the second face, and wherein the firstangle and the second angle have the same value.
 4. The lamp of claim 3,wherein the value is in the range of 40° to 55°.
 5. The lamp of claim 1,wherein the exterior facet profile comprises a first profile at a firstend of the facet and a second profile at a second end of the facet,wherein the first profile is different from the second profile.
 6. Thelamp of claim 5, wherein the first profile is dimensionally larger thanthe second profile.
 7. The lamp of claim 5, wherein the ratio of thefirst profile to the second profile is 1 or greater.
 8. The reflector ofclaim 1, wherein the reflector has an outer peripheral edge, and whereinthe facet edge tapers from the outer peripheral edge toward the centeraxis.
 9. The lamp of claim 1, wherein the reflector has an aperture thatis coaxial with the center axis.
 10. The lamp of claim 1, furthercomprising a light source with an optical axis that aligns with thecenter axis of the reflector, wherein the reflector is spaced apart fromthe light source and spaced apart from a top portion of the envelopealong the center axis.
 11. A lamp, comprising: a light-emitting diodedevice with an optical axis; a reflector spaced apart from thelight-emitting diode device, the reflector having a center axis alignedwith the optical axis and comprising a plurality of facets disposedcircumferentially about the center axis, the facets having an exteriorfacet profile with a first face, a second face opposing the first face,and a facet edge disposed therebetween; an envelope in surroundingrelation to the reflector; and a heat dissipating assembly with a heatdissipating element spaced apart from the outer surface of the envelopeforming an air gap.
 12. The lamp of claim 11, wherein the reflectorforms an internal reflection lens.
 13. The lamp of claim 11, wherein thefacets comprise a first facet and a second facet that is adjacent thefirst facet, and wherein the first face of the first facet and thesecond face of the second facet form a valley therebetween.
 14. The lampof claim 13, wherein an end of the first face of the first facet and anend of the second face of the second facet meet at a point to form thevalley.
 15. The lamp of claim 11, wherein the reflector comprises anaperture that proximate the center axis.
 16. The lamp of claim 15,wherein the reflector comprises an element that covers at least part ofthe aperture.
 17. The lamp of claim 11, wherein the first face and thesecond face of the facets are configured to reflect a first amount oflight emitted by the light source back to a first portion of theenvelope and to refract a second amount of light emitted by the lightsource to a second portion of the envelope, wherein the first portion issubjacent to the second portion along the optical axis.
 18. A reflectorfor use in a lamp, said reflector comprising: a plurality of facetsdisposed circumferentially about a center axis forming an outerperipheral edge, the facets having an exterior facet profile with afirst face, a second face opposing the first face, and a facet edgedisposed therebetween, wherein the exterior facet profile comprises afirst profile proximate the outer peripheral edge of the reflector and asecond profile proximate the center axis that is different fromdifferent from the first profile.
 19. The reflector of claim 18, whereinthe first face and the second face form sides of a triangle.
 20. Thereflector of claim 19, wherein the triangle of the first profile issmaller than the triangle of the second profile.